According to Greg Hillebrand, Ph.D., a recognized subject matter expert at P&G on the subject, there may be a real correlation between the amount of porphyrins and skin aging as described in the following technical excerpt that offers the best understanding we have today on the matter: "In pilosebaceous follicles, porphyrins are produced by propionibacterium acnes (P. acnes) that are normal inhabitants of the human skin and the pilosebaceous ducts. Porphyrins are highly fluorescent pores containing P. acnes and the associated porphyrins appear red-orange when facial skin is illuminated with long wavelength UVA radiation. The intensity of the follicular fluorescence and its extent of facial involvement is known to be proportional to the density of P. acnes. Porphyrin fluorescence appears first on the nose and chin, and then increases in incidence through adulthood and declines after the age of 50, possibly reflecting the rate of sebum secretion. Porphyrins may also have cytotoxic and comedogenic potential. With exposure to the sun, porphyrins can release singlet oxygen that in turn can oxidize lipids (lipid peroxidation) in the skin yielding irritating and cytotoxic lipid peroxides that can cause skin damage. Thus, the presence of porphyrins in the follicular pores may enhance or accelerate hyperpigmentation, wrinkling and other signs of photo-aging by sun exposure."